- Constellation Energy is a leading supplier of energy products and services to wholesale and retail electric and natural gas customers. It owns a diversified fleet of generating units located throughout the United States and Canada, totaling approximately 7,100 megawatts of generating capacity, and is among the leaders pursuing the development of new nuclear plants in the United States. The company delivers electricity and natural gas through the Baltimore Gas and Electric Company (BGE), its regulated utility in Central Maryland. A FORTUNE 500 company headquartered in Baltimore, Constellation Energy had revenues of $19.8 billion in 2008.